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Fertilized Egg
Begins to exist when the sperm penetrates the egg within the first 12 hours prior to the pronuclei joining. -
Hour 12
Fertilization -
Hour 12
Pronuclei Join Together -
Zygote Stage Begins
Occurs when the two pronuclei join together within the first 12 hours. -
Hours 30-36
First Round of Mitosis -
Hour 40
Second Round of Mitosis -
Hours 50-60
Third Round of Mitosis -
Morula Formed
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Embryo Stage Begins
Occurs after the third cleavage when the morula forms. -
Day 6
64 Cell Embryo Called a Blastocyst -
Hatching
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Day 8-10
Implantation -
Day 8-10
Ectopic Pregnancy Could Occur -
Day 12
hCG Begins to be Secreted -
Day 12
Disc with Streak on the Underside forms the Mesoderm -
Day 14-22
Neural Tube Forms -
Day 15
First Missed Period -
Day 21
Heart Begins to Beat, Arm and Leg Buds Appear, Yolk Sac Makes RBCs. -
Day 34-36
Face Plates Forming -
Day 34-36
Cleft Lip or Palate May Occur -
Week 6
Muscles Form, Bent Neck, Webbed Hands and Feet, Segmented Back -
Week 7
Fingers and Toes Separate, Eyes & Ears Formed -
Day 50
Genitalia Begins to Differentiate, Eyelids Fuse, Amnion Surrounds Fetus -
Fetal Stage Begins
Occurs when all the baby's organs have formed and now move into a period of further development and mass growth. -
Week 9-11
Chorionic Villi Sampling Could be Performed -
Week 14-15
Amniocentesis Could be Performed -
Month 6-7
Eyes Open, Fat Added Under Skin, Head out of Proportion to the Body
